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        <h2>
          <span class="refentrytitle">#ifndef</span>
        </h2>
        <p>#ifndef — 
      Conditional reading of code.
                </p>
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      <div class="refsect1">
        <a id="idp87472416"></a>
        <h2>Description</h2>
        <p>
      If the specified macro is not defined then <span class="emphasis"><em>#ifndef</em></span> can
    incorporate text into an orchestra upto the next
    <span class="emphasis"><em>#end</em></span>.  
    This is similar to, but independent of, the <a class="link" href="ScoreMacros.html" title="Score Macros"><em class="citetitle">macro system in the score
    language</em></a>.
    </p>
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        <h2>Syntax</h2>
        <pre class="synopsis"><span class="command"><strong>#ifndef</strong></span> NAME</pre>
        <pre class="synopsis">....</pre>
        <pre class="synopsis"><span class="command"><strong>#else</strong></span> </pre>
        <pre class="synopsis">....</pre>
        <pre class="synopsis"><span class="command"><strong>#end</strong></span> </pre>
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        <a id="idp87481424"></a>
        <h2>Performance</h2>
        <p>
      Note that the <span class="emphasis"><em>#ifndef</em></span> can be nested, like in the C preprocessor language.
    </p>
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        <a id="idp87483136"></a>
        <h2>See Also</h2>
        <p>
      <a class="link" href="dollar.html" title="$NAME"><em class="citetitle">$NAME</em></a>, 
      <a class="link" href="define.html" title="#define"><em class="citetitle">#define</em></a>,
      <a class="link" href="ifdef.html" title="#ifdef"><em class="citetitle">#ifdef</em></a>.
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        <h2>Credits</h2>
        <p>
      </p>
        <table border="0" summary="Simple list" class="simplelist">
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            <td>Author: John ffitch</td>
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            <td>University of Bath/Codemist Ltd.</td>
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            <td>Bath, UK</td>
          </tr>
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            <td>April 2005</td>
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        <p>
    </p>
        <p>New in Csound5 (and 4.23f13)</p>
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